The Lswarm are the primary antagonists in the "Yu-Gi-Oh!" main card packs and "Duel Terminal" series. They are a species of mechanical beings created by Tierra to discontinue the growth of life in the Duel Terminal World. Though not by name, the Shaddolls and Infernoids are descended from the same viruses that created the Lswarm, making them Lswarms by nature.
Steelswarms are the first of the dark species introduced. They look and are named after bugs, which makes them come in many different forms. They usually delve in shades of red, black and gold, but the primary insects also have their own color specific to them. Though they look organic and are not Machine-type in card form, they are considered to be biomechanical.
Evilswarm is the name of beings that were once of a different species than the Steelswarm but were infected by the Lswarm Virus. They come in many varieties, originating from at least ten different clans, but the traits they all share are ghostly color schemes and insect-like armor growths.
Unlike their predecessors, Shaddolls actually resembles machines. Just like Evilswarms, they were originally enemies of the Steelswarm who have been reformatted into biomechanical beings. The traits they share this time around are their dark colors and the wires coming out of their bodies meant to look like puppeteering strings.
Infernoids are beings who emerged from a proxied Shaddoll virus that was uploaded into a Qliphort through contact with a Shaddoll. Infernoids come in many shapes, but they mainly share a brownish-red armor color with different colored accents in their non-armored parts. They also have canisters on their body that are the same color as the accents, which are used to store a liquified energy extracted from pyroxenes.
In this ancient times of the Duel Terminal World, two deities named Sophia and Tierra came to the world sparked life into it. However, while Sophia wanted life to grow and prosper peacefully, Tierra wanted all life to become extinct. To carry out its mission of ending all life on the planet, Tierra seeded the growth of mechanical insects called the "Steelswarm." After it did, Sophia sealed Tierra in a machine under her Sacred Tree and left the Steelswarm to grow anyway.
The Second World Clan Wars
Over time, the Steelswarm came to unwillingly share the planet with several other clans: the Gishki, the Gem-Knights, the Gusto, the Laval and the Vylons. After the emergence of the Vylons, the Steelswarm were sealed away by them and became unable to do anything while they were around. When the Laval started a war with the Gem-Knights for no reason, the Vylons tried to intervene and became distracted enough for the Steelswarm to attack the Gishki and Gusto. The Vylons eventually persuaded the Laval and Gem-Knights to stop fighting and they shared their technology with the four clans' most powerful warriors in order to end the Steelswarm once and for all, or so everyone thought.
Threat of the Evilswarms
At some point, a Steelswarm grub consumed a fossilized Fabled body and its lingering dark magic caused the infectious genes in the grub to mutate into the "Lswarm" virus. As the virus started spreading, it reanimated the dead from both the first world and the second, turning them into biomechanical zombies with insect parts. Among the infected were all three of the Ice Barrier dragons: Trishula, Gungnir, and Brionac, though they had yet to be brought back to life. The virus got so out of hand that the undead managed to destroy the Vylons and back all of the other clans into a corner. With the threat of the four extinction imminent, a group of cosmic knights called "Constellars" came down and started to push back the forces of the undead.
In order to aid the Constellars, Gem-Knights Zircon and Lapis used the power of their pyroxenes to create Gem-Knight fusions and increase their power, resulting in Zircon transforming into Gem-Knight Master Diamond and Lapis' twin, Lazuli, being transformed into Gem-Knight Seraphinite. In becoming Seraphinite, a ninth pyroxene was created which allowed beings who were friends to combine together. Using this power allowed Seraphinite to combine the bodies of several Constellars to form the Constellar Ptolemy M7.
At the same time, a Gishki named Noelia became corrupted by Steelswarm influence when she tried using them as sacrifices for a rebirth spell. In her madness, she resurrected Steelswarm Hercules, the most powerful Steelswarm to have fallen at the hands of the Vylons. She also unfossilized the bodies of the three Ice Barrier Dragons in the distance, allowing them to attack other lands without anyone noticing. While Hercules started to destroy Gishki Ritual Mirrors, Noelia snapped back to her sanity and used herself as the final sacrifice for the rebirth spell. Hercules was drawn to the ritual but was destroyed when Noelia sacrificed her life energy at the right moment.
Two of the Ice Barrier Dragons were presumably taken down before they were discovered by the Constellars, but Trishula, now called Evilswarm Ouroboros, was still ravaging the land. The only things strong enough to stand up to Ouroboros was the Ptolemy M7, though it was still not strong enough. After a few sacrifices, one of which being Gem-Knight Lapis, the Ptolemy M7 managed to finally slay Ouroboros and the last of the Lswarms.
During the conflicts, a shrine at the Mist Valley began to gather energy for reasons unknown. The shrine was demolished and out from it emerged Sophia, Goddess of Rebirth. Sophia was angered by the constant warring of the clans and decided to eliminate all life on the planet to make sure all of the Lswarms would be gone. Sophia generated proxy versions of the beings she intended to destroy as her soldiers and used her power of destruction to unmake and remake the originals.
Due to all of the fighting, Gem-Knight Master Diamond became fatally injured, so he passed his 7 pyroxenes along with Lapis' to Seraphinite. Seraphinite used the pyroxene's power to combine herself with the Ptolemy M7 and Sophia's pyroxene of creation, forming Constellar Sombre. In order to aid Sombre, one of the Constellars used the last Gishki Mirror to absorb the Lswarm energy off the dead bodies of the Ice Barrier Dragons and combine them with Sophia's power of destruction, resulting in him becoming Evilswarm Kerykion. The two then started to attack the jewel on Sophia's forehead so that they could banish her to the astral plane. Their assault lasted for days due to the durability of the jewel, but they finally smashed it and banished Sophia. With Sophia defeated, Kerykion and Sombre took off for parts unknown, but the Lswarm virus still lingered on.
The Emergence of the Shaddolls
Due to the lingering Lswarm virus, the corpses of various Gem-Knights, including Lapis, became combined into an amalgamated knight due to Lapis' link to her pyroxene. Sensing that something was wrong, Kerykion and Sombre returned to the land in order to prepare for another war. Sombre used her pyroxenes to create spirit dragons called the Yang Zing, while Kerykion went to hunt down the evil at its source. This resulted in him confronting and fighting the amalgamated knight called Cairngorgon. Due to Kerykion not wanting to hurt the Gem-Knights, Cairngorgon defeated and absorbed him. Kerykeion's dark powers mutated the Lswarm virus in Cairngorgon's head, causing the knight's body to die and give birth to the Shaddoll Core and the Shaddoll Virus. The Core then combined with Lapis' part of Cairngorgon's corpse to create The Construct.
Upon its creation, the Construct used the Shaddoll Virus to resurrect various members of the fallen clans as Shaddolls, including Winda, Priestess of Gusto. Sombre eventually found them and engaged them in battle, but two of her Yang Zing were corrupted almost instantly. Out of nowhere, a cosmic protectorate called the Satellarknights came down and attempted to assist in the battle. However, one was absorbed by the Shaddoll virus which gained it the power to "merge constellations."
The Construct then used this power to corrupt two more members of the Yang Zing and rip the pyroxenes from them, creating El Shaddoll Grysta from the remains of Cairngorgon. While this battle was going on, the Construct ordered Shaddoll Winda to hurt the Naturia Sacred Tree far away. She did, causing the tree to uproot and start floating high above the world. At the same time, a machine came up with the sacred tree and activated the "Qliphort Protocol," which ejected a Qliphort scouting machine that took Winda Prisoner by absorbing her. The program also summoned the pyroxenes to the Sacred Tree by way of ripping them out of Grysta, which killed it and returned it to the shambles of Cairngorgon that it was.
The Machine ripped the pyroxenes out of Grysta so it could energize the power cores of various other Qliphorts, including their most powerful unit: "Apoqliphort Towers." Upon arriving, Towers immediately devastated the Shaddolls, leaving only the Construct standing. Before he was absorbed, Kerykion used his Gishki mirror to summon the Nekroz clan to the battle. When they arrived, they used their rituals to channel the Ice Barrier dragons Trishula, Gungnir, and Brionac in preparation. Towers then latched the Construct onto itself and entangled its wire wings around its legs. As Towers had immobilized the Construct, the Nekroz used the powers of the dragons to freeze the Construct and Towers, seemingly ending the threat.
Absorbing Winda caused the Qliphort Scout to malfunction; "Allow C:\tierra\qliphort.exe ? <Y/N>…[Y] Booting in Autonomy Mode…" This new program forced the Qliphorts to eject their cores, and out of the pure energy came the Infernoids; ten satanic biomechanoids intent on destroying the Sacred Tree. While 9 were destroyed almost as soon as they emerged, their 9th member, Infernoid Devyaty, slipped away during the battle to use steal the Ice dragons' power from between dimensions and unfreeze the Construct. Upon unfreezing the Construct, the two merged together and assaulted the Yang Zing and the Tellarknights.
The Yang Zing produced a legendary spear with which to destroy this new form, and though the form was shattered, it would not stay dead for long. Devyaty's head survived and hacked into the machine under the Sacred Tree to free a giant Infernoid called Tierra from within. Tierra used its power of rebirth to bring Lapis' body back to life inside the Construct's head. The Construct then used Lapis' power to merge with the Tellarknights and Devyaty's head to create a conduit form that would make Tierra even stronger. Meanwhile, Tierra went around the battlefield and consumed the dead Infernoids to gain their power.
When the two were ready, they fused together to form Tierra, Source of Destruction. Due to the full rebirth of Tierra, the machine under the Sacred Tree started glowing with the power of the pyroxene. The machine revived Cairngorgon and the Shaddoll Core and merged them with the 10 pyroxene, creating Zefraath. Zefraath and Tierra then fought a battle that lasted for over 3 years. Though Zefraath won the battle, it is unclear if any more remnants of the Lswarm or Shaddoll viruses remained after Tierra's destruction.
- Steelswarm Hercules: Hercules was the most powerful Steelswarm to exist. He was killed by the combined might of the Vylon's technology and the other four clans' toughest warriors. He was resurrected by Gishki Noelia for a short time but was destroyed when Noelia gave her life to perfect a revival ritual.
- Steelswarm Roach: Once another mindless Steelswarm grub, a Sentinal who came into contact with a Vylon fragment and evolved to hate his purpose. He was one of the pivotal warriors to fight against the Steelswarm, Sophia, and Tierra.
- Gishki Noelia: Noelia was the only person on the planet to side with the Steelswarms but not be infected by the Lswarm virus. In trying to harness the power of the Steelswarm, she accidentally killed her best friend and the ensuing madness she suffered through caused her to look and act like a Steelswarm.
- Vylon Disigma: A combined form of the last Vylons, corrupted by Gishki Noelia. While hiding her madness, Noelia manages to infect the last few Vylons with the Steelswarms' influence and the form they take is destroyed by Gem-Knight Pearl.
- Evilswarm Bahamut and Ophion: The weaker two of the Ice Barrier dragons. Although they were revived and caused so much devastation, they were defeated by some unknown force prior to being discovered by the Constellars.
- Evilswarm Ouroboros: A corrupted version of the strongest ice dragon in history, Ouroboros was responsible for the deaths of Gem-Knights Lapis and Master Diamond.
- Evilswarm Kerykeion: A former Constellar who kept his sanity and nobility after infusing the power of the dead Lswarm Ice Barrier dragons into himself.
- Cairngorgon, the Antiluminescent Knight: The corpses of a few Gem-Knights corrupted by the Lswarm virus, this knight became the patient zero for the Shaddoll Virus by absorbing Evilswarm Kerykeion.
- The Construct: An evil mechanical zombie modeled after Gem-Knight Lapis. The Construct is the most powerful Shaddoll, staving off death twice and almost ending all life on the planet.
- El Shaddoll Winda: One of the first beings brought back to life as a Shaddoll, Winda was the one who damaged the Naturia Sacred Tree and facilitated the creation of the Infernoids.
- Infernoid Devyaty: What could be considered the Construct's accomplice in almost bringing on the apocalypse. It's the only Infernoid to have successfully completed its mission of freeing Tierra.
- Infernoid Tierra: The Mastermind behind the creation of the Lswarms and a deity of destruction.
- Tierra, Source of Destruction: Tierra's final form: composed of Sophia and Tierra's most powerful creations. It is destroyed by Zefraath, restoring some of the corrupted beings back to their lives.
Steelswarms in the game are center around using their grubs as tributes to summon the named insects and activate their effects upon being summoned properly.
Due to the nature of their archetypal cards calling them "lswarms," the Evilswarms are both archetypal support for Steelswarms and their own independent deck. They center around using slower effects to put a damper on the opponent's active cards.
Shaddolls are a slightly faster deck that centers around fusion summoning their six different fusion monsters at varying times. Their ace card "El Shaddoll Construct" has been banned as of 2014.
Infernoids are a deck comprised of monsters who can only be special summoned, but have powerful and direct effects and can easily outnumber an opponent's monsters. They do this by sending huge chunks of their player's deck to the graveyard.